Numerous building structures have been designed to fill the demand for an inexpensive, storable and transportable structure. Many such designs achieve their "portability" through total assembly and disassembly of their structural components: walls, floors, roofs, etc. This requires significant preparation time and creates problems associated with the parts needed and the skill involved in assembly and disassembly. Other designs require no on-site assembly at all, and are shipped "whole". However, these designs are inherently bulky and difficult to move and store.
A further shortcoming of most present designs is their lack of a structural foundation. This requires that they be anchored to a separate external foundation, or have no foundation at all, resulting in structural instability.